1. Field of Invention
The invention relates to a vehicle drive unit, such as a hybrid vehicle and an electric vehicle, obtaining a vehicle drive force by a drive motor.
2. Description of Related Art
A conventional vehicle drive unit is shown in back elevation in FIG. 6 with FIG. 7 a side cross sectional diagram of the drive unit of FIG. 6.
In a conventional hybrid vehicle and an electric vehicle, an inverter (not shown), connected to an electric motor and a generator 57, is separately arranged from a hybrid drive unit 55, the vehicle drive unit. As shown in FIGS. 6 and 7, the inverter and the hybrid drive unit 55 are connected with a motor lead wires 53 routed, or pulled out, from a rear cover 52 side, which is at an opposite side to an output gear 51 of the electric motor 50.
In this structure, the upper face, side face and the rear cover 52 of the hybrid drive unit 55 are enlarged to obtain a space for routing, or positioning, the motor lead wires 53 connecting to terminals 56. As a result, the parts, especially the rear cover portion is prone to interfere with a side member of the vehicle.
Especially in the case where the inverter could be integrally disposed on an upper portion of a hybrid drive unit 55, that is the necessary space is available, the inverter can not be so disposed because a terminal 56 for routing a motor lead wire is in the way, i.e., is located at that position.
In view of the above problems associated with the related art, an object of the invention is to provide a vehicle drive unit, in which an inverter can be disposed on the upper portion of the vehicle drive unit and a rear cover side of the vehicle drive unit is compactly covered.
In order to achieve the foregoing object, according to the invention, a vehicle drive unit that obtains a drive force for driving a vehicle from an electric motor comprises the electric motor, a differential unit, a gear unit transmitting a drive force from the electric motor to the differential unit, a cover covering the electric motor, an inverter disposed on the cover, and a lead wire from the electric motor disposed in neighborhood of an output gear of the electric motor, the output gear a part of the gear unit, and in a space structured by diameter differences between the output gear and the electric motor so as to route to the outside of the cover at a position corresponding to the output gear. The electric motor and the inverter are electrically connected through the lead wire.
The lead wire is structured from a first lead wire, terminal and a second lead wire, the terminal is disposed in a portion of the cover near to the output gear by penetrating the cover. The electric motor and the terminal are connected with the first lead wire, and the inverter and the terminal are connected with the second lead wire.
A lead wire from the electric motor is connected to a stator of the electric motor.
An inverter case, in which the inverter is disposed is integrated with the cover, and a grooving space is formed between the rear portion of the cover and the inverter case. A heat sink for cooling the inverter is formed in a part of the cover between the inverter and the electric motor. A chamber portion is formed on the rear portion of the cover corresponding to the rear portion of the electric motor which substantially outlines, i.e., follows the contour of, the stator of the electric motor.
According to the invention, a lead wire from the electric motor is disposed in the vicinity of an output gear of the electric motor and in a space structured by diameter differences between the output gear and the electric motor. The lead wire is routed to the outside of the cover from the space. Therefore, the upper face portion of the electric motor of the vehicle drive unit, which is used as a space for routing or positioning the lead wire in the conventional unit, is used as a space for disposing the inverter. The inverter can then be disposed on the upper face of the vehicle drive unit, which comparatively available space in the vehicle. As a result, the vehicle drive unit is compactly structured with the inverter.
Further, the lead wire is not routed from the rear portion of the cover or the rear cover portion. Therefore, the rear cover portion is compactly structured. As a result, interference between the vehicle drive unit and vehicle side members is appreciably prevented when the vehicle drive unit is mounted.
The terminal, which is a comparatively large member, is disposed a portion of the cover near to the output gear. Therefore, the space structured by the diameter differences between the output gear and the electric motor is effectively used.
A brushless DC motor can be used as an electric motor. In such a case, the structure of the vehicle drive unit is simplified.
Because the grooving space is formed, interference with side members of a vehicle is prevented.
The heat sink for cooling the inverter is formed at a position corresponding to the rotor portion of the electric motor along with the outline of the rotor. Therefore, the heat sink is formed without wasted space.
A chamfer portion is formed on the rear portion of the cover along the outline of the stator of the electric motor, and the outline of the cover is formed along with the electric motor. Therefore, unneeded thickness of the rear portion of the cover is prevented and, then, interference with side members of a vehicle is prevented.